1. Field of the Invention
This disclosure is generally related to the preparation of media, for example labels and tags, and more particularly to the preparation of media carrying objects, for example semiconductor chips, electrical traces and/or radio frequency identification (RFID) circuits.
2. Description of the Related Art
A large variety of applications employ media of various types for a multitude of purposes. For example, tags and labels allow the identification, tracking and/or inventorying of luggage, parcels, boxes, merchandise, files or folders, products, and/or other items. Tags and labels also allow the identification and/or tracking of people, for example patients in medical facilities or employees in a work setting. Tags and labels also allow the identification of locations, such as exhibits in a museum, shelves in a store or file room, and/or rooms in a building or office. Licenses or registration stamps permit identification, tracking and/or verification that taxes and/or other fees have been collected on associated items such as vehicles, alcohol, and/or tobacco products among other items.
While the media may take a large variety of forms, it commonly includes a face sheet or substrate which may carry optically encoded information such as printed machine-readable and/or human-readable information. The media may include an adhesive layer carried by the face sheet, allowing the media to be physically associated with an object, place or person to be identified or tracked. The adhesive layer may employ a self-adhesive formulation. In such a case, a release liner or backing overlies the adhesive layer. The release liner is selectively removable by an end user to expose the adhesive layer for fixing or attaching the media to an object, place, and/or person. Alternatively, the adhesive layer may employ a formulation that requires some type of activation, such as the application of heat and/or moisture before adhering the media to an object, place, and/or person, or that employs special adhesives, face sheet materials or face sheet coatings that eliminate the need for a release liner. Such media typically omits the release liner and is commonly referred to as linerless media.
Some media includes objects either carried on the media or embedded within the media. For example, a class of media commonly referred to as radio frequency identification (RFID) tags includes electrical circuits in the form of radio frequency (RF) transponders. These RFID circuits typically employ an electrical trace forming an antenna on a substrate, and a semiconductor chip carried by the substrate and electrically coupled to the antenna. The RFID tag may include a discrete power source (i.e., active RFID tag), or may employ power derived from an interrogation signal (i.e., passive RFID tag) produced by an RFID reader. The RFID circuit emits an RF signal in response to an RF interrogation signal, the emitted RF signal typically encoding information stored in the RFID tag. The RFID tag may employ encoding, compression, encryption, and/or other forms of data management and data security.
Manufacturing of RFID tags typically starts with a continuous sheet or roll of media, comprising a face sheet, an adhesive layer and a release liner. The release liner is temporarily separated from the face sheet and adhesive layer, RFID circuits are inserted or formed automatically therebetween, and the release liner is reattached to the adhesive layer. The RFID circuits are often spaced along a length of the continuous sheet of media at predefined increments. RFID circuits may also be spaced laterally across the continuous sheet.
After placement or formation of the RFID circuits, the media is converted to an appropriate size for distribution to end users. Conversion commonly employs cutting, perforating, and/or scoring the media or specific layers of the media to form individual tags and labels. For example, the face sheet may be cut, perforated and/or scored to form individual labels of a desired shape and size. The adhesive layer and/or release liner may likewise be cut, perforated and/or scored. For example, the release liner may be perforated or scored to allow an end user to easily tear individual tags or labels from a roll. Conversion may also employ cutting the continuous sheet or rolls longitudinally, to create multiple sheets or rolls of an appropriate width. Conversion may also employ cutting the continuous sheet or rolls laterally to create sheets or rolls of appropriate length or diameter, respectively. The converted sheets or rolls are distributed to end users, who typically print identifying information on individual labels.
The converting process applies substantial pressures and forces to the media, which increases the probability of damage to objects carried by the media such as semiconductor chips and/or antennas and thus decreasing manufacturing yields. While semiconductor chips and antennas are thin in absolute terms, the semiconductor chips and/or antenna create an inconsistency in the thickness of the tag or label, which may be large in relative terms with respect to the nominal thickness of the tag or label. This inconsistency in thickness may have an adverse affect on the converting tools, increasing wear and shortening the useful life of the converting tools. This inconsistency in thickness may additionally, or alternatively, have an adverse affect on printing tools, for example thermal printheads and/or platens, increasing wear and shortening the life of printing tools used to print on the media. Further, the printing tools apply substantial pressures and forces to the media, increasing the probability of damage to the RFID circuits, and thus decreasing manufacturing yields. A method and apparatus to form media carrying objects, for example RFID circuits, but which avoids the foregoing drawbacks is thus desirable.